Atomic Mass Calculator

atomic mass unit(u)
x10⁻²⁷ kg


The atomic mass of an element is the mass of a single atom of that element, expressed in atomic mass units (amu). The atomic mass unit is defined as 1/12 of the mass of a carbon-12 atom.

The atomic mass of an element can be calculated by determining the masses of its isotopes and the relative abundances of each isotope. For example, if an element has two isotopes with masses m1 and m2 and relative abundances f1 and f2, respectively, the atomic mass of the element can be calculated as:

M = f1m1 + f2m2

The masses of isotopes can be determined experimentally using mass spectrometry, while their relative abundances can be determined by measuring their concentrations in a sample.

It is important to note that the atomic mass is a weighted average of the masses of all isotopes of an element, and that it reflects the actual composition of the element in a sample. The atomic mass can be useful in a number of applications, such as in determining the molecular weight of a compound or in calculating the relative atomic mass of an element.